Low-concentration carbon dioxide recycling and refining device

Abstract

The invention relates to the technical field of carbon dioxide recovery and refining, in particular to a low-concentration carbon dioxide recovery and refining device which comprises a water washing desulfurization unit and a carbon dioxide absorption unit, the detection unit is used for respectively detecting the carbon dioxide concentration, the gas rising speed of the gas inlet of the second absorption tower, the carbon dioxide absorption amount in the second absorption tower, the flow velocity of the raw material gas and the flow velocity of carbon dioxide; and the control unit is used for respectively determining the pressure and the vertical height of the spray head according to the gas rising speed and the carbon dioxide absorption amount, and determining the temperature of the rich liquid cooler according to the carbon dioxide concentration increment of the first absorption tower. The problem that in the prior art, when a carbon dioxide absorbent entering the first absorption tower again makes contact with raw material gas, the contact area is reduced, and the carbon dioxide recovery efficiency is low is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide recovery and purification, and particularly to a low-concentration carbon dioxide recovery and purification device. Background Art

[0002] The efficient recovery and utilization of low-concentration carbon dioxide ( , with a concentration usually lower than 20%) has become a key challenge in industrial emission reduction and resource-based transformation. However, existing technologies generally face bottleneck problems such as low recovery efficiency, high energy consumption, and poor economy in practical applications.

[0003] Chinese Patent Publication No.: CN102019132B discloses a carbon dioxide recovery system, including: an absorber that introduces exhaust gas containing carbon dioxide into contact with an absorbent and causes the absorbent to absorb carbon dioxide in the exhaust gas, and the absorber reversibly absorbs or releases carbon dioxide above or below a predetermined temperature level; a regenerator that releases carbon dioxide in the absorbent by heating the absorbent that has absorbed carbon dioxide in the absorber; a reflux pipe that returns the absorbent regenerated from the regenerator to the absorber; and a filter that is used to introduce at least part of the absorbent, remove solids aggregated in the introduced absorbent, and return the absorbent after removing the solids to a position near the part where the absorbent is introduced.

[0004] It can be seen that in the carbon dioxide recovery system, part of the raw gas leaves the second absorption tower without contacting the carbon dioxide absorbent, resulting in low utilization rate of carbon dioxide recovery, and due to the absorption of carbon dioxide by the carbon dioxide absorbent in the first absorption tower, the viscosity increases, resulting in a decrease in the contact area when the carbon dioxide absorbent re-entering the first absorption tower contacts the raw gas, leading to the problem of low carbon dioxide recovery efficiency. Summary of the Invention

[0005] For this reason, the present invention provides a low-concentration carbon dioxide recovery and purification device to overcome the problems in the prior art that part of the raw gas leaves the second absorption tower without contacting the carbon dioxide absorbent, resulting in low utilization rate of carbon dioxide recovery, and due to the absorption of carbon dioxide by the carbon dioxide absorbent in the first absorption tower, the viscosity increases, resulting in a decrease in the contact area when the carbon dioxide absorbent re-entering the first absorption tower contacts the raw gas, leading to the problem of low carbon dioxide recovery efficiency.

[0006] To achieve the above object, the present invention provides a low-concentration carbon dioxide recovery and purification device, including: A water washing and desulfurization unit for cooling and desulfurizing the raw gas by water washing; A carbon dioxide absorption unit, which is connected to the water washing desulfurization unit, includes an absorption component for adsorbing carbon dioxide in the raw gas by a carbon dioxide absorbent and a desorption component connected to the absorption component for releasing carbon dioxide in the carbon dioxide absorbent to obtain gaseous carbon dioxide. The absorption component includes a first absorption tower and a second absorption tower, a spray head arranged at the top of the second absorption tower for spraying the carbon dioxide absorbent, a moving component connected to the spray head for controlling the vertical movement of the spray head, and a rich liquid cooler for cooling the absorption-state carbon dioxide absorbent output from the first absorption tower; A detection unit, which is connected to the carbon dioxide absorption unit, is used for respectively detecting the carbon dioxide concentration, the gas rising speed at the gas inlet of the second absorption tower, the carbon dioxide absorption amount in the second absorption tower, the flow rate of the raw gas, and the flow rate of carbon dioxide; A control unit, which is respectively connected to the water washing desulfurization unit, the carbon dioxide absorption unit, and the detection unit, is used for respectively determining the pressure and the vertical height of the spray head according to the gas rising speed and the carbon dioxide absorption amount, and determining the temperature of the rich liquid cooler according to the increase amount of the carbon dioxide concentration in the first absorption tower.

[0007] Further, the absorption component further includes: A wire mesh demister, which is arranged above the spray head for eliminating the bubbles generated by the combination of the carbon dioxide absorbent and the raw gas; A first rich liquid pump, which is connected to the bottom of the first absorption tower for pumping out the absorption-state carbon dioxide absorbent at the bottom of the first absorption tower; A rich liquid circulation pump, which is arranged between the first absorption tower and the rich liquid cooler for circulating the absorption-state carbon dioxide absorbent at the bottom of the first absorption tower to the top of the first absorption tower; A second rich liquid pump, which is arranged between the first absorption tower and the second absorption tower for pumping the absorption-state carbon dioxide absorbent at the bottom of the second absorption tower into the top of the first absorption tower; A lean liquid cooler, which is arranged on the lean liquid pipeline connected to the spray head for cooling the carbon dioxide absorbent after the release flowing through the lean liquid pipeline; A filter, which is arranged between the lean liquid cooler and the spray head for filtering the carbon dioxide absorbent after the release flowing through the lean liquid pipeline.

[0008] Further, the desorption component includes: Rich and lean liquid heat exchanger, which is connected to the first rich liquid pump through the rich liquid delivery pipeline and connected to the lean liquid cooler through the lean liquid delivery pipeline, and is used for heat exchange of the carbon dioxide absorbent released at the end flowing through the lean liquid delivery pipeline and the carbon dioxide absorbent in the absorption state flowing through the rich liquid delivery pipeline; Analysis tower, which is connected to the rich and lean liquid heat exchanger through the rich liquid delivery pipeline, and is used for releasing carbon dioxide in the carbon dioxide absorbent in the absorption state to obtain gaseous carbon dioxide; Lean liquid pump, which is connected to the bottom of the analysis tower and is used for pumping the carbon dioxide absorbent released at the end at the bottom of the analysis tower into the lean liquid delivery pipeline; Gas output pipeline, which is connected to the top of the analysis tower and is used for outputting the gaseous carbon dioxide.

[0009] Furthermore, the detection unit includes: First carbon dioxide concentration sensor, which is arranged in the intake passage of the cooling water scrubbing tower in the water washing desulfurization unit and is used for detecting the carbon dioxide concentration before water washing cooling; Second carbon dioxide concentration sensor, which is arranged in the gas output pipeline and is used for detecting the carbon dioxide concentration in the gas output pipeline; Third carbon dioxide concentration sensor, which is arranged in the first absorption tower and is used for detecting the carbon dioxide concentration in the first absorption tower; First gas flow sensor, which is arranged in the intake passage of the cooling water scrubbing tower in the water washing desulfurization unit and is used for detecting the flow rate of the raw gas flowing through the intake passage; Second gas flow sensor, which is arranged in the gas output pipeline and is used for detecting the flow rate of carbon dioxide in the gas output pipeline; Ultrasonic flowmeter, which is arranged at the gas inlet of the second absorption tower and is used for detecting the gas rising speed of the raw gas at the gas inlet of the second absorption tower; Online pH sensor, which is arranged at the bottom of the second absorption tower and is used for detecting the pH value of the carbon dioxide absorbent at the bottom of the second absorption tower to determine the carbon dioxide absorption amount of the carbon dioxide absorbent.

[0010] Further, the control unit is connected to the first carbon dioxide concentration sensor, the second carbon dioxide concentration sensor, the first gas flow sensor, and the second gas flow sensor, and is configured to respectively obtain the carbon dioxide concentration before the cooling water wash, the carbon dioxide concentration in the gas output pipeline, the flow rate of the raw material gas in the intake passage, and the carbon dioxide flow rate in the gas output pipeline. The initial detection amount of carbon dioxide in the raw material gas is determined based on the carbon dioxide concentration before the cooling water wash and the flow rate of the raw material gas in the intake passage. The carbon dioxide output amount of the analysis component is determined based on the carbon dioxide concentration in the gas output pipeline and the carbon dioxide flow rate in the gas output pipeline. The recovery state of carbon dioxide is determined based on the difference between the initial detection amount of carbon dioxide in the raw material gas and the carbon dioxide output amount of the analysis component, where, If the ratio of the difference to the initial detection amount is greater than or equal to a preset loss ratio, it is determined that the carbon dioxide recovery is abnormal, and the carbon dioxide concentration, the gas rising speed, the carbon dioxide absorption amount, the flow rate of the raw material gas, and the carbon dioxide flow rate are collected to further determine the abnormal state; If the ratio of the difference to the initial detection amount is less than the preset loss ratio, it is determined that the carbon dioxide recovery is normal.

[0011] Further, the initial detection amount is the integral value of the product of the function of the carbon dioxide concentration before the cooling water wash with respect to time and the function of the flow rate of the raw material gas in the intake passage with respect to time within a preset sampling period.

[0012] Further, the carbon dioxide output amount is the integral value of the product of the function of the carbon dioxide concentration in the gas output pipeline with respect to time and the function of the carbon dioxide flow rate in the gas output pipeline with respect to time within a preset sampling period.

[0013] Further, the control unit is connected to the nozzle, and is configured to further determine that the nozzle is abnormal based on the gas rising speed being less than the first preset gas rising speed and the carbon dioxide absorption amount being greater than the preset carbon dioxide absorption amount, and increase the pressure of the nozzle.

[0014] Further, the control unit is connected to the moving component, and is configured to further determine that the vertical height of the nozzle is abnormal based on the gas rising speed being greater than or equal to the first preset gas rising speed and less than the second preset gas rising speed and based on the carbon dioxide absorption amount being less than or equal to the preset carbon dioxide absorption amount, and increase the vertical height of the nozzle through the moving component.

[0015] Further, the control unit is connected to the rich liquid cooler, and is configured to further determine that the temperature of the rich liquid cooler is abnormal according to that the increase in the carbon dioxide concentration in the first absorption tower is greater than a preset increase in the carbon dioxide concentration, and reduce the temperature of the rich liquid cooler.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows. The present invention further determines that the spray head is abnormal according to that the gas rising speed is less than a first preset gas rising speed and the carbon dioxide absorption amount is greater than a preset carbon dioxide absorption amount, and increases the pressure of the spray head, thereby solving the problem that due to the impact of the raw material gas, some metal powders of the wire mesh demister fall into the spray head, resulting in a change in the direction of the spray head, causing the spray head to spray the carbon dioxide absorbent towards the gas inlet of the second absorption tower, hindering the entry of the raw material gas into the second absorption tower, resulting in a slower entry speed of the raw material gas, and further causing the vertical position of the contact between the raw material gas and the carbon dioxide absorbent to shift downward. Since the vertical position of the contact between the raw material gas and the carbon dioxide absorbent shifts downward, a part of the carbon dioxide absorbent may have been re-polymerized, resulting in some raw material gas leaving the second absorption tower without contacting the carbon dioxide absorbent, resulting in that carbon dioxide is not completely absorbed into the carbon dioxide absorbent, resulting in that the ratio of the difference between the carbon dioxide output amount output by the analysis component within a preset sampling period and the initial detection amount of carbon dioxide in the raw material gas to the initial detection amount is greater than or equal to a preset loss ratio, and further resulting in a low utilization rate of carbon dioxide recovery. By increasing the pressure of the spray head, the flow rate of the raw material gas going upward is reduced, the probability of some metal powders of the wire mesh demister falling into the spray head due to the impact of the raw material gas and causing a change in the direction of the spray head is reduced, and the utilization rate of carbon dioxide recovery is improved.

[0017] Further, by obtaining the carbon dioxide absorption amount absorbed by the carbon dioxide absorbent in the second absorption tower, it is determined to increase the vertical height of the spray head through the moving component according to the gas rising speed being greater than or equal to the first preset gas rising speed and less than the second preset gas rising speed and according to the carbon dioxide absorption amount absorbed by the carbon dioxide absorbent in the second absorption tower being less than or equal to the preset carbon dioxide absorption amount. This solves the problem that when the wire mesh demister causes some of its metal powders to fall into the spray head due to the impact of the raw gas, resulting in a change in the direction of the spray head, causing the spray head to spray the carbon dioxide absorbent towards the gas inlet of the second absorption tower, blocking the entry of the raw gas into the second absorption tower, resulting in a slower entry speed of the raw gas. At this time, some of the carbon dioxide absorbent reaches the bottom of the second absorption tower before contacting the raw gas. At this time, the raw gas just leaves the second absorption tower in large quantities during the time interval when the spray head sprays the next carbon dioxide absorbent, resulting in carbon dioxide not being fully absorbed into the carbon dioxide absorbent, resulting in the ratio of the difference between the carbon dioxide output amount output by the analysis component within the preset sampling period and the initial detection amount of carbon dioxide in the raw gas to the initial detection amount being greater than or equal to the preset loss ratio, and further resulting in a low utilization rate of carbon dioxide recovery. By increasing the vertical height of the spray head through the moving component, the time for the carbon dioxide absorbent to be sprayed from the spray head to fall to the bottom of the second absorption tower is increased, the probability of contact between the carbon dioxide absorbent and the raw gas is increased, the situation where the carbon dioxide absorbent reaches the bottom of the second absorption tower without contacting the raw gas is avoided, and the utilization rate of carbon dioxide recovery is improved.

[0018] Further, by obtaining the increase amount of carbon dioxide concentration in the first absorption tower, it is determined that the compactness of the carbon dioxide absorbent is abnormal and the temperature of the rich liquid cooler is reduced according to the increase amount of carbon dioxide concentration in the first absorption tower being greater than the preset carbon dioxide concentration increase amount. This solves the problem that due to the carbon dioxide absorbent in the first absorption tower absorbing carbon dioxide, its viscosity increases, resulting in a decrease in the contact area when the carbon dioxide absorbent re-enters the first absorption tower and contacts the raw gas, thereby weakening the absorption ability of the carbon dioxide absorbent to carbon dioxide, and further resulting in carbon dioxide being trapped in the first absorption tower and being difficult to be absorbed by the carbon dioxide absorbent, and further resulting in the ratio of the difference between the carbon dioxide output amount output by the analysis component within the preset sampling period and the initial detection amount of carbon dioxide in the raw gas to the initial detection amount being greater than or equal to the preset loss ratio, and further resulting in a low efficiency of carbon dioxide recovery. By reducing the temperature of the rich liquid cooler, the temperature of the carbon dioxide absorbent re-entering the first absorption tower is lower than the temperature of the raw gas entering the first absorption tower. When the two contact, part of the moisture in the raw gas forms moisture when cooled, and the moisture enters the carbon dioxide absorbent, reducing the viscosity of the carbon dioxide absorbent, improving the absorption ability of the carbon dioxide absorbent to carbon dioxide, and improving the efficiency of carbon dioxide recovery.

[0019] Further, the control unit determines the carbon dioxide recovery status according to the difference between the initial detection amount of carbon dioxide in the raw material gas and the carbon dioxide output amount of the analysis component, and determines that the carbon dioxide recovery is abnormal according to the ratio of the difference to the initial detection amount being greater than or equal to the preset loss ratio, solving the problem that the recovery utilization rate of carbon dioxide is difficult to quantitatively track, solving the problem that the decline in the recovery utilization rate of carbon dioxide has not been recognized for a long time, and improving the recovery utilization rate of carbon dioxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic structural diagram of a low-concentration carbon dioxide recovery and purification device according to an embodiment of the present invention; Figure 2 It is a structural block diagram of a low-concentration carbon dioxide recovery and purification device according to an embodiment of the present invention; Figure 3 It is a structural block diagram of a carbon dioxide absorption unit in a low-concentration carbon dioxide recovery and purification device according to an embodiment of the present invention; Figure 4 It is a schematic structural diagram of a carbon dioxide absorption unit in a low-concentration carbon dioxide recovery and purification device according to an embodiment of the present invention; In the figure, 1 - water washing and desulfurization unit, 2 - carbon dioxide absorption unit, 3 - compression and adsorption unit, 4 - refrigeration and liquefaction unit, 11 - cooling water washing tower, 12 - desulfurization tower, 21 - absorption component, 22 - analysis component, 31 - dehumidification component, 32 - drying component, 210 - first absorption tower, 211 - second absorption tower, 212 - spray head, 213 - moving component, 214 - rich liquid cooler, 215 - first pipeline, 216 - vent water washing tower, 217 - second pipeline, 218 - wire mesh demister, 219 - first rich liquid pump, 2110 - rich liquid circulation pump, 2111 - second rich liquid pump, 2112 - lean liquid cooler, 2113 - lean liquid conveying pipeline, 2114 - filter, 220 - rich and lean liquid heat exchanger, 221 - rich liquid conveying pipeline, 222 - analysis tower, 223 - lean liquid pump, 224 - gas output pipeline. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] In order to make the objectives and advantages of the present invention clearer, the present invention will be further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention and do not limit the protection scope of the present invention.

[0023] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] Please refer to Figure 1 、 Figure 2 、 Figure 3 and Figure 4 as shown, which are respectively the structural schematic diagram, the structural block diagram, the structural block diagram of the carbon dioxide absorption unit, and the structural schematic diagram of the carbon dioxide absorption unit of the low-concentration carbon dioxide recovery and refining device according to the embodiments of the present invention.

[0025] The low-concentration carbon dioxide recovery and refining device according to the embodiments of the present invention includes: A water washing and desulfurization unit 1 for cooling and desulfurizing the raw gas by water washing, including a cooling water washing tower 11 for cooling the raw gas and a desulfurization tower 12 connected to the cooling water washing tower 11 for desulfurizing the raw gas; Specifically, the components of the raw gas include: hydrogen sulfide, oxygen, nitrogen, water vapor, hydrocarbon organic matter, carbon monoxide, carbon dioxide, sulfur dioxide, and nitrogen oxides.

[0026] Specifically, the process of cooling and washing the raw gas by the cooling water washing tower is a conventional technical means well-known to those skilled in the art, and the process of cooling and washing the raw gas will not be described in detail here; the principle of desulfurization is to add an alkaline substance such as sodium hydroxide to react with the sulfur-containing substance to complete desulfurization. The desulfurization process and principle are also well-known to those skilled in the art, so it will not be described in detail here.

[0027] A carbon dioxide absorption unit 2, which is connected to the water washing and desulfurization unit 1, includes an absorption assembly 21 for adsorbing carbon dioxide in the raw gas by a carbon dioxide absorbent and an analysis assembly 22 connected to the absorption assembly 21 for releasing carbon dioxide in the carbon dioxide absorbent to obtain gaseous carbon dioxide. The absorption assembly 21 includes a first absorption tower 210 and a second absorption tower 211, a nozzle 212 arranged at the top of the second absorption tower 211 for spraying the carbon dioxide absorbent, a moving assembly 213 connected to the nozzle 212 for controlling the vertical movement of the nozzle 212, and a rich liquid cooler 214 for cooling the absorption-state carbon dioxide absorbent output from the first absorption tower 210; the first absorption tower 210 is connected to the second absorption tower 211 through a first pipeline 215; In implementation, the moving component 213 can be an electric telescopic rod. The principle of the electric telescopic rod for adjusting the nozzle to move vertically is that the telescopic movement of the electric telescopic rod drives the nozzle to move along the vertical direction. The pipeline connected to the nozzle in the second absorption tower is a flexible pipeline with good flexibility. The flexible pipeline can be a rubber hose or a spring protection hose.

[0028] In this embodiment, the absorption component 21 further includes an emptying and water washing tower 216, which is connected to the second absorption tower 211 through a second pipeline 217, and is used to remove the carbon dioxide absorbent entrained in the raw material gas after carbon dioxide removal to obtain a quasi-exhaust raw material gas, and discharge the quasi-exhaust raw material gas.

[0029] Specifically, the meaning of the absorption state is the state of absorbing carbon dioxide; the carbon dioxide absorbent at the end of release is the carbon dioxide absorbent output by the stripping tower that has completed the carbon dioxide release process and absorbed the heat of the absorption state carbon dioxide absorbent that is not for recycling output by the first absorption tower.

[0030] A detection unit, which is connected to the carbon dioxide absorption unit 2, and is used to detect the carbon dioxide concentration, the gas rising speed at the gas inlet of the second absorption tower 211, the carbon dioxide absorption amount in the second absorption tower 211, the flow rate of the raw material gas, and the flow rate of carbon dioxide respectively; A control unit, which is respectively connected to the water washing and desulfurization unit 1, the carbon dioxide absorption unit 2, and the detection unit, and is used to determine the pressure and the vertical height of the nozzle 212 according to the gas rising speed and the carbon dioxide absorption amount respectively, and determine the temperature of the rich liquid cooler 214 according to the increase in the carbon dioxide concentration of the first absorption tower 210.

[0031] In this embodiment, the low-concentration carbon dioxide recovery and purification device further includes a compression and adsorption unit 3, which is connected to the carbon dioxide absorption unit 2, and includes a dehumidification component 31 for removing moisture in the gaseous carbon dioxide and a drying component 32 for removing moisture in the gaseous carbon dioxide; Among them, the dehumidification component 31 includes a dehumidifier, a buffer tank for stabilizing the gas pressure fluctuation in the dehumidification component 31, a compressor for receiving the gas from the buffer tank and compressing it, and a high-pressure cold dryer for deeply dehumidifying the high-pressure and high-temperature gas output by the compressor, which are connected end to end in sequence. The drying component 32 is a drying bed skid.

[0032] Specifically, the compressor is a three-stage compression. After each stage of compression, the gas enters the cooler in the compressor to be cooled by cooling water, enters the water separator in the compressor to separate water, and then enters the next stage of compression. A pressure regulating valve is provided at the compressor outlet and the buffer tank inlet to control the pressure to 0.105 MPa to prevent the compressor from drawing a vacuum.

[0033] The compressed mixed gas first passes through a high-pressure cold dryer to reduce the temperature to 10°C and separate most of the water, and then enters the drying bed skid. By using a combination of two water separation methods, namely, cooling and water separation by the high-pressure cold dryer and molecular sieve adsorption dehydration by the drying bed skid, the water content index of the final product is ensured. This is better than the process effect of using only the drying bed skid alone, and the quality is more guaranteed. At the same time, since most of the condensed water is removed during the cooling and water separation process, the dehydration load of the drying bed skid is reduced, the regeneration times are reduced, and the regeneration energy consumption is saved.

[0034] In implementation, the drying bed skid regeneration adopts the "zero gas consumption" regeneration technology. That is: no carbon dioxide gas and external gas are consumed during the regeneration process of the drying bed skid. The regeneration process is divided into two stages: hot blow and cold blow. During the hot blow process, a blower is used to send air into an electric heater to be heated and then enter the regenerated drying bed skid for heating. After the drying bed skid is heated, it enters the cooling and cold blow stage. A blower is used to send cold air into the drying bed skid, and the cold air takes away the heat of the drying bed skid and then enters the cooler to be cooled to room temperature. The cooled cold air enters the blower inlet and is sent into the drying bed skid again for cooling, and this cycle is used.

[0035] In this embodiment, the low-concentration carbon dioxide recovery and refining device further includes a refrigeration and liquefaction unit 4, which is connected to the compression and adsorption unit 3 to liquefy the gaseous carbon dioxide into liquid carbon dioxide, including a precooler, a condenser, and a refrigeration unit.

[0036] Specifically, the mixed gas enters the precooler, exchanges heat with the condenser, is cooled to 8°C and then enters the condenser, where it exchanges heat with the refrigerant Freon from the refrigeration unit and is cooled to -25°C. At the same time, the carbon dioxide component in the mixed gas is liquefied into liquid carbon dioxide. The refrigeration unit uses a screw unit with Freon as the refrigerant, is equipped with a refrigerant economizer, and adopts the low-temperature barrel pump technology. Due to the pressure drop of the pipeline resistance during the flow of the refrigerant, the pressure of the refrigerant in the pipeline is lower than the saturated steam and vaporizes, resulting in waste of the refrigerant's cooling capacity. The use of a refrigerant economizer in combination with a low-temperature barrel pump increases the refrigeration efficiency of the refrigerant by at least 10%. At the same time, since the heat exchanger is filled with the refrigerant, the heat transfer area occupied by the gas phase volatilization is reduced, saving the heat exchanger space.

[0037] Specifically, the absorption assembly 21 further includes: A wire mesh demister 218, which is arranged above the spray head 212 to eliminate the bubbles generated by the combination of the carbon dioxide absorbent and the raw gas; A first rich liquid pump 219, which is connected to the bottom of the first absorption tower 210 to pump out the carbon dioxide absorbent in the absorption state at the bottom of the first absorption tower 210; Rich liquid circulation pump 2110, which is arranged between the first absorption tower 210 and the rich liquid cooler 214, and is used to circulate the carbon dioxide absorbent in the absorption state at the bottom of the first absorption tower 210 to the top of the first absorption tower 210; Second rich liquid pump 2111, which is arranged between the first absorption tower 210 and the second absorption tower 211, and is used to pump the carbon dioxide absorbent in the absorption state at the bottom of the second absorption tower 211 into the top of the first absorption tower 210; Lean liquid cooler 2112, which is arranged on the lean liquid delivery pipeline 2113 connected to the spray head 212, and is used to cool the carbon dioxide absorbent that has completed the release flowing through the lean liquid delivery pipeline 2113; Filter 2114, which is arranged between the lean liquid cooler 2112 and the spray head 212 and is connected to the lean liquid delivery pipeline 2113, and is used to filter the carbon dioxide absorbent that has completed the release flowing through the lean liquid delivery pipeline 2113.

[0038] Specifically, the analysis component 22 includes: Rich and lean liquid heat exchanger 220, which is connected to the first rich liquid pump 219 through the rich liquid delivery pipeline 221 and is connected to the lean liquid cooler 2112 through the lean liquid delivery pipeline 2113, and is used to exchange heat between the carbon dioxide absorbent that has completed the release flowing through the lean liquid delivery pipeline 2113 and the carbon dioxide absorbent in the absorption state flowing through the rich liquid delivery pipeline 221; Analysis tower 222, which is connected to the rich and lean liquid heat exchanger 220 through the rich liquid delivery pipeline 221, and is used to release carbon dioxide from the carbon dioxide absorbent in the absorption state to obtain gaseous carbon dioxide; Lean liquid pump 223, which is connected to the bottom of the analysis tower 222, and is used to pump the carbon dioxide absorbent that has completed the release at the bottom of the analysis tower 222 into the lean liquid delivery pipeline 2113; Gas output pipeline 224, which is connected to the top of the analysis tower 222, and is used to output the gaseous carbon dioxide.

[0039] Specifically, the detection unit includes: First carbon dioxide concentration sensor, which is arranged in the intake passage of the cooling water washing tower 11 in the water washing desulfurization unit 1, and is used to detect the carbon dioxide concentration before the cooling water washing; Second carbon dioxide concentration sensor, which is arranged on the gas output pipeline 224, and is used to detect the carbon dioxide concentration of the gas output pipeline 224; Third carbon dioxide concentration sensor, which is arranged in the first absorption tower 210, and is used to detect the carbon dioxide concentration in the first absorption tower 210; A first gas flow sensor is disposed in the intake passage of the cooling water scrubbing tower 11 in the water scrubbing and desulfurization unit 1 for detecting the flow rate of the raw gas flowing through the intake passage. A second gas flow sensor is disposed in the gas output pipeline 224 for detecting the flow rate of carbon dioxide in the gas output pipeline 224. An ultrasonic flowmeter is disposed at the gas inlet of the second absorption tower 211 for detecting the gas rising speed of the raw gas at the gas inlet of the second absorption tower 211. An on-line pH sensor is disposed at the bottom of the second absorption tower 211 for detecting the pH value of the carbon dioxide absorbent at the bottom of the second absorption tower 211 to determine the carbon dioxide absorption amount of the carbon dioxide absorbent.

[0040] Specifically, carbon dioxide (CO2) reacts with an alkaline absorbent (such as NaOH, MEA, etc.) to form carbonate or bicarbonate, resulting in a decrease in the pH value of the absorbent. The reaction general formula is: CO2 + 2OH - →CO3 2- +H2O or CO2 + OH - →HCO3 - .

[0041] The initial pH of the alkaline absorbent is relatively high (such as the pH of the NaOH solution ≈ 13). As the CO2 absorption amount increases, OH - is consumed, and the generated HCO3 - / CO3 2- causes the pH to gradually decrease (down to 8 - 10). The pH change amount has a quantitative relationship with the CO2 absorption amount. The pH sensor detects the H + activity in the absorbent through a glass electrode and converts the signal into a pH value. Through a calibration curve or algorithm, the pH change amount is converted into the CO2 absorption amount (mol / L), and the formula is: Δ[CO2] ∝ (pH0 - pH t ), where pH0 is the initial value and pH t is the real-time value.

[0042] Specifically, the control unit is connected to the first carbon dioxide concentration sensor, the second carbon dioxide concentration sensor, the first gas flow sensor, and the second gas flow sensor to respectively obtain the carbon dioxide concentration before the cooling water wash, the carbon dioxide concentration in the gas output pipeline 224, the flow rate of the raw material gas in the intake passage, and the carbon dioxide flow rate in the gas output pipeline 224. The initial detection amount of carbon dioxide in the raw material gas is determined according to the carbon dioxide concentration before the cooling water wash and the flow rate of the raw material gas in the intake passage. The carbon dioxide output amount of the analysis component 22 is determined according to the carbon dioxide concentration in the gas output pipeline 224 and the carbon dioxide flow rate in the gas output pipeline 224. The recovery state of carbon dioxide is determined according to the difference between the initial detection amount of carbon dioxide in the raw material gas and the carbon dioxide output amount of the analysis component 22. Among them, if the ratio of the difference to the initial detection amount is greater than or equal to the preset loss percentage, it is determined that the carbon dioxide recovery is abnormal, and the carbon dioxide concentration, the gas rising speed, the carbon dioxide absorption amount, the flow rate of the raw material gas, and the carbon dioxide flow rate are collected to further determine the abnormal state; if the ratio of the difference to the initial detection amount is less than the preset loss percentage, it is determined that the carbon dioxide recovery is normal.

[0043] Optionally, when the carbon dioxide absorption unit 2 is under the conditions of temperature: 30°C to 50°C, pressure: 0.1 MPa to 0.3 MPa, the optional range of the preset loss percentage is [15%, 20%].

[0044] Preferably, in this embodiment, when the carbon dioxide absorption unit 2 is under the conditions of temperature: 30°C to 50°C, pressure: 0.1 MPa to 0.3 MPa, the preferred embodiment of the preset loss percentage is 18%.

[0045] Those skilled in the art can understand that the preferred setting of 18% is a preferred embodiment when the carbon dioxide absorption unit 2 is under the conditions of temperature: 30°C to 50°C, pressure: 0.1 MPa to 0.3 MPa. In actual application or implementation, those skilled in the art can make adaptive adjustments or replacements to the preset loss percentage according to the changes in the temperature and pressure conditions of the carbon dioxide absorption unit 2.

[0046] In implementation, the control unit determines the recovery state of carbon dioxide according to the difference between the initial detection amount of carbon dioxide in the raw material gas and the carbon dioxide output amount of the analysis component 22, and determines that the carbon dioxide recovery is abnormal according to the ratio of the difference to the initial detection amount being greater than or equal to the preset loss percentage, which solves the problem that the recovery utilization rate of carbon dioxide is difficult to quantify and track, and solves the problem that the decrease in the recovery utilization rate of carbon dioxide has not been recognized for a long time, and improves the recovery utilization rate of carbon dioxide.

[0047] Specifically, the initial detection quantity is the integral value of the product of the function of the carbon dioxide concentration before the cooling water wash with respect to time and the function of the flow rate of the raw material gas in the intake passage with respect to time within a preset sampling period.

[0048] Specifically, the carbon dioxide output quantity is the integral value of the product of the function of the carbon dioxide concentration in the gas output pipeline with respect to time and the function of the flow rate of the carbon dioxide in the gas output pipeline with respect to time within a preset sampling period.

[0049] Optionally, when the carbon dioxide absorption unit 2 is under the conditions of temperature: 30°C to 50°C, pressure: 0.1 MPa to 0.3 MPa, the optional range of the preset sampling period is [10 min, 20 min].

[0050] Preferably, in this embodiment, when the carbon dioxide absorption unit 2 is under the conditions of temperature: 30°C to 50°C, pressure: 0.1 MPa to 0.3 MPa, the preferred embodiment of the preset sampling period is 15 min.

[0051] Those skilled in the art can understand that the preferred setting of 15 min is a preferred embodiment when the carbon dioxide absorption unit 2 is under the conditions of temperature: 30°C to 50°C, pressure: 0.1 MPa to 0.3 MPa. In actual application or implementation, those skilled in the art can make adaptive adjustments or replacements to the preset sampling period according to the changes in the temperature and pressure conditions of the carbon dioxide absorption unit 2.

[0052] Specifically, the control unit is connected to the nozzle 212, and is used to further determine that the nozzle 212 is abnormal according to the fact that the gas rising speed is less than the first preset gas rising speed and the carbon dioxide absorption quantity is greater than the preset carbon dioxide absorption quantity, and increase the pressure of the nozzle 212.

[0053] Optionally, when the carbon dioxide absorption unit 2 is under the conditions of temperature: 30°C to 50°C, pressure: 0.1 MPa to 0.3 MPa, the optional range of the first preset gas rising speed is [0.3 m / s, 0.5 m / s].

[0054] Preferably, in this embodiment, when the carbon dioxide absorption unit 2 is under the conditions of temperature: 30°C to 50°C, pressure: 0.1 MPa to 0.3 MPa, the preferred embodiment of the first preset gas rising speed is 0.4 m / s.

[0055] Those skilled in the art can understand that the preferred setting of 0.4 m / s is a preferred embodiment when the carbon dioxide absorption unit 2 is under the conditions of temperature: 30°C to 50°C, pressure: 0.1 MPa to 0.3 MPa. In actual application or implementation, those skilled in the art can make adaptive adjustments or replacements to the first preset gas rising speed according to the changes in the temperature and pressure conditions of the carbon dioxide absorption unit 2.

[0056] Optionally, when the carbon dioxide absorption unit 2 is under the conditions of temperature: 30°C to 50°C, pressure: 0.1 MPa to 0.3 MPa, the optional range of the preset carbon dioxide absorption amount is [0.25 kg / m³, 0.35 kg / m³].

[0057] Preferably, in this embodiment, when the carbon dioxide absorption unit 2 is under the conditions of temperature: 30°C to 50°C, pressure: 0.1 MPa to 0.3 MPa, the preferred embodiment of the preset carbon dioxide absorption amount is 0.30 kg / m³.

[0058] Those skilled in the art can understand that the preferred setting of 0.30 kg / m³ is a preferred embodiment when the carbon dioxide absorption unit 2 is under the conditions of temperature: 30°C to 50°C, pressure: 0.1 MPa to 0.3 MPa. In actual application or implementation, those skilled in the art can make adaptive adjustments or replacements to the preset carbon dioxide absorption amount according to the changes in the temperature and pressure conditions of the carbon dioxide absorption unit 2.

[0059] In implementation, when the carbon dioxide absorption unit 2 is under the conditions of temperature: 30°C to 50°C, pressure: 0.1 MPa to 0.3 MPa, when the value of the gas rising speed less than the first preset gas rising speed is within 0.1 m / s and the value of the carbon dioxide absorption amount greater than the preset carbon dioxide absorption amount is within 0.10 kg / m³, the pressure of the nozzle 212 is adjusted to 1.1 times the current pressure of the nozzle 212; when the value of the gas rising speed less than the first preset gas rising speed exceeds 0.1 m / s, for every 0.1 m / s exceeded, the pressure of the nozzle 212 is adjusted to 1.1 times the current pressure of the nozzle 212, and when the value of the carbon dioxide absorption amount greater than the preset carbon dioxide absorption amount exceeds 0.10 kg / m³, for every 0.10 kg / m³ exceeded, the pressure of the nozzle 212 is adjusted to 1.1 times the current pressure of the nozzle 212; for example, in a possible embodiment, the value of the gas rising speed less than the first preset gas rising speed is 0.2 m / s, and the value of the carbon dioxide absorption amount greater than the preset carbon dioxide absorption amount is 0.20 kg / m³. At this time, the pressure of the nozzle 212 is adjusted to 1.1×1.1×1.1 = 1.331 times the original pressure of the nozzle 212.

[0060] In implementation, by further determining that the spray head 212 is abnormal according to the gas rising speed being less than the first preset gas rising speed and the carbon dioxide absorption amount being greater than the preset carbon dioxide absorption amount, and increasing the pressure of the spray head 212, the problem that due to the impact of the raw material gas, some metal powders of the wire mesh demister 218 fall into the spray head 212, resulting in a change in the direction of the spray head 212, causing the spray head 212 to spray the carbon dioxide absorbent towards the gas inlet of the second absorption tower 211, blocking the entry of the raw material gas into the second absorption tower 211, resulting in a slowdown in the entry speed of the raw material gas, and further causing the vertical position of the contact between the raw material gas and the carbon dioxide absorbent to shift downward. Since the vertical position of the contact between the raw material gas and the carbon dioxide absorbent shifts downward, a part of the carbon dioxide absorbent may have re-polymerized, resulting in some of the raw material gas leaving the second absorption tower 211 without contacting the carbon dioxide absorbent, causing the carbon dioxide not to be fully absorbed into the carbon dioxide absorbent, resulting in the ratio of the difference between the carbon dioxide output amount output by the analysis component 22 and the initial detection amount of carbon dioxide in the raw material gas to the initial detection amount being greater than or equal to the preset loss ratio during the preset sampling period, and further resulting in a low utilization rate of carbon dioxide recovery. By increasing the pressure of the spray head 212, the flow rate of the raw material gas going upward is reduced, the probability of the direction of the spray head 212 changing due to some metal powders of the wire mesh demister 218 falling into the spray head 212 caused by the impact of the raw material gas is reduced, and the utilization rate of carbon dioxide recovery is improved.

[0061] Specifically, the control unit is connected to the moving component 213, and is used to further determine that the vertical height of the spray head 212 is abnormal according to the gas rising speed being greater than or equal to the first preset gas rising speed and less than the second preset gas rising speed and according to the carbon dioxide absorption amount being less than or equal to the preset carbon dioxide absorption amount, and increase the vertical height of the spray head 212 through the moving component 213.

[0062] Optionally, when the carbon dioxide absorption unit 2 is under the conditions of temperature: 30°C to 50°C, pressure: 0.1 MPa to 0.3 MPa, the optional range of the second preset gas rising speed is [0.6 m / s, 1.0 m / s].

[0063] Preferably, in this embodiment, when the carbon dioxide absorption unit 2 is under the conditions of temperature: 30°C to 50°C, pressure: 0.1 MPa to 0.3 MPa, the preferred embodiment of the second preset gas rising speed is 0.8 m / s.

[0064] Those skilled in the art can understand that the preferred setting of 0.8 m / s is a preferred embodiment when the carbon dioxide absorption unit 2 is under the conditions of temperature: 30°C to 50°C, pressure: 0.1 MPa to 0.3 MPa. In actual application or implementation, those skilled in the art can make adaptive adjustments or replacements to the second preset gas rising speed according to the changes in the temperature and pressure conditions of the carbon dioxide absorption unit 2.

[0065] In implementation, when the carbon dioxide absorption unit 2 is under the conditions of temperature: 30°C to 50°C, pressure: 0.1 MPa to 0.3 MPa, when the value of the gas rising speed being greater than or equal to the first preset gas rising speed and less than the second preset gas rising speed is within 0.1 m / s and at the same time the value of the carbon dioxide absorption amount being less than the preset carbon dioxide absorption amount is within 0.10 kg / m³, the vertical height of the nozzle 212 is adjusted to 1.2 times the current vertical height of the nozzle 212. When the value of the carbon dioxide absorption amount being less than the preset carbon dioxide absorption amount exceeds 0.10 kg / m³, for every 0.10 kg / m³ exceeded, the vertical height of the nozzle 212 is adjusted to 1.2 times the current vertical height of the nozzle 212. When the value of the gas rising speed being greater than or equal to the first preset gas rising speed and less than the second preset gas rising speed exceeds 0.1 m / s, for every 0.1 m / s exceeded, the vertical height of the nozzle 212 is adjusted to 1.2 times the current vertical height of the nozzle 212. For example, in a possible embodiment, the value of the carbon dioxide absorption amount being less than the preset carbon dioxide absorption amount is 0.20 kg / m³, and the value of the gas rising speed being greater than or equal to the first preset gas rising speed and less than the second preset gas rising speed is 0.2 m / s. At this time, the vertical height of the nozzle 212 is adjusted to 1.2×1.2×1.2 = 1.728 times the original vertical height of the nozzle 212.

[0066] In implementation, by obtaining the carbon dioxide absorption amount absorbed in the carbon dioxide absorbent in the second absorption tower 211, and based on the gas rising speed being greater than or equal to the first preset gas rising speed and less than the second preset gas rising speed, and based on the carbon dioxide absorption amount absorbed in the carbon dioxide absorbent in the second absorption tower 211 being less than or equal to the preset carbon dioxide absorption amount, it is determined to increase the vertical height of the spray head 212 through the moving component 213. This solves the problem that when the wire mesh demister 218 causes some of its metal powders to fall into the spray head 212 due to the impact of the raw material gas, resulting in a change in the direction of the spray head 212, causing the spray head 212 to spray the carbon dioxide absorbent towards the gas inlet of the second absorption tower 211, hindering the entry of the raw material gas into the second absorption tower 211, resulting in a slower entry speed of the raw material gas. At this time, some of the carbon dioxide absorbent reaches the bottom of the second absorption tower 211 before contacting the raw material gas. At this time, the raw material gas just leaves the second absorption tower 211 in large quantities during the time interval when the spray head 212 sprays the next carbon dioxide absorbent, resulting in not all carbon dioxide being absorbed into the carbon dioxide absorbent, resulting in the ratio of the difference between the carbon dioxide output amount output by the analysis component 22 and the initial detection amount of carbon dioxide in the raw material gas to the initial detection amount being greater than or equal to the preset loss ratio during the preset sampling period, and further resulting in a low utilization rate of carbon dioxide recovery. By increasing the vertical height of the spray head 212 through the moving component 213, the time for the carbon dioxide absorbent to spray from the spray head 212 to reach the bottom of the second absorption tower 211 is increased, the probability of contact between the carbon dioxide absorbent and the raw material gas is increased, the situation where the carbon dioxide absorbent reaches the bottom of the second absorption tower 211 before contacting the raw material gas is avoided, and the utilization rate of carbon dioxide recovery is improved.

[0067] Specifically, the control unit is connected to the rich liquid cooler 214, and is used to further determine that the temperature of the rich liquid cooler 214 is abnormal based on the increase in the carbon dioxide concentration in the first absorption tower 210 being greater than the preset carbon dioxide concentration increase amount, and reduce the temperature of the rich liquid cooler 214.

[0068] Optionally, when the carbon dioxide absorption unit 2 is under the conditions of temperature: 30°C to 50°C, pressure: 0.1 MPa to 0.3 MPa, the optional range of the preset carbon dioxide concentration increase amount is [0.10 kg / m³, 0.20 kg / m³].

[0069] Preferably, in this embodiment, when the carbon dioxide absorption unit 2 is under the conditions of temperature: 30°C to 50°C, pressure: 0.1 MPa to 0.3 MPa, the preferred embodiment of the preset carbon dioxide concentration increase amount is 0.15 kg / m³.

[0070] Those skilled in the art can understand that the preferred setting of 0.15 kg / m³ is a preferred embodiment when the carbon dioxide absorption unit 2 is under the conditions of temperature: 30°C to 50°C, and pressure: 0.1 MPa to 0.3 MPa. In actual application or implementation, those skilled in the art can make adaptive adjustments or replacements to the preset carbon dioxide concentration increase according to the changes in the temperature and pressure conditions of the carbon dioxide absorption unit 2.

[0071] In implementation, when the carbon dioxide absorption unit 2 is under the conditions of temperature: 30°C to 50°C, and pressure: 0.1 MPa to 0.3 MPa, when the value of the carbon dioxide concentration increase greater than the preset carbon dioxide concentration increase is within 0.03 kg / m³, the temperature of the rich liquid cooler 214 is reduced by 0.5°C. When the value of the carbon dioxide concentration increase greater than the preset carbon dioxide concentration increase exceeds 0.03 kg / m³, for every 0.01 kg / m³ exceeded, the temperature of the rich liquid cooler 214 is reduced by 0.5°C. For example, in a possible embodiment, the value of the carbon dioxide concentration increase greater than the preset carbon dioxide concentration increase is 0.05 kg / m³, and at this time, the temperature of the rich liquid cooler 214 is reduced by 0.5°C + 0.5°C + 0.5°C = 1.5°C.

[0072] In implementation, by obtaining the carbon dioxide concentration increase of the first absorption tower 210, and determining that the density of the carbon dioxide absorbent is abnormal according to the carbon dioxide concentration increase of the first absorption tower 210 being greater than the preset carbon dioxide concentration increase, the temperature of the rich liquid cooler 214 is reduced. This solves the problem that due to the carbon dioxide absorbent in the first absorption tower 210 absorbing carbon dioxide, its viscosity increases, resulting in a decrease in the contact area when the carbon dioxide absorbent re-entering the first absorption tower 210 contacts the raw gas, thereby causing the absorption capacity of the carbon dioxide absorbent for carbon dioxide to become weaker, and further causing carbon dioxide to be trapped in the first absorption tower 210 and difficult to be absorbed by the carbon dioxide absorbent, and further causing the ratio of the difference between the carbon dioxide output amount output by the analysis component 22 and the initial detection amount of carbon dioxide in the raw gas to the initial detection amount within the preset sampling period to be greater than or equal to the preset loss ratio, and further resulting in low carbon dioxide recovery efficiency. By reducing the temperature of the rich liquid cooler 214, the temperature of the carbon dioxide absorbent re-entering the first absorption tower 210 is lower than the temperature of the raw gas entering the first absorption tower 210. When the two contact, part of the moisture in the raw gas forms moisture when cooled, and the moisture enters the carbon dioxide absorbent, reducing the viscosity of the carbon dioxide absorbent, improving the absorption capacity of the carbon dioxide absorbent for carbon dioxide, and improving the carbon dioxide recovery efficiency.

[0073] So far, the technical solution of the present invention has been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A low-concentration carbon dioxide recovery and purification device, characterized in that, Including: A water washing desulfurization unit for cooling the raw gas by water washing and desulfurizing it; A carbon dioxide absorption unit connected to the water washing desulfurization unit, including an absorption component for adsorbing carbon dioxide in the raw gas by a carbon dioxide absorbent and a regeneration component connected to the absorption component for releasing carbon dioxide in the carbon dioxide absorbent to obtain gaseous carbon dioxide. The absorption component includes a first absorption tower and a second absorption tower, a spray head arranged at the top of the second absorption tower for spraying the carbon dioxide absorbent, a moving component connected to the spray head for controlling the vertical movement of the spray head, and a rich liquid cooler for cooling the absorption-state carbon dioxide absorbent output from the first absorption tower; A detection unit connected to the carbon dioxide absorption unit for respectively detecting the carbon dioxide concentration, the gas rising speed at the gas inlet of the second absorption tower, the carbon dioxide absorption amount in the second absorption tower, the flow rate of the raw gas, and the flow rate of carbon dioxide; A control unit respectively connected to the water washing desulfurization unit, the carbon dioxide absorption unit, and the detection unit for respectively determining the pressure of the spray head and the vertical height of the spray head according to the gas rising speed and the carbon dioxide absorption amount, and determining the temperature of the rich liquid cooler according to the increase amount of carbon dioxide concentration in the first absorption tower.

2. The low-concentration carbon dioxide recovery and purification device according to claim 1, characterized in that The absorption component further includes: A wire mesh demister arranged above the spray head for eliminating the bubbles generated by the combination of the carbon dioxide absorbent and the raw gas; A first rich liquid pump connected to the bottom of the first absorption tower for pumping out the absorption-state carbon dioxide absorbent at the bottom of the first absorption tower; A rich liquid circulation pump arranged between the first absorption tower and the rich liquid cooler for circulating the absorption-state carbon dioxide absorbent at the bottom of the first absorption tower to the top of the first absorption tower; A second rich liquid pump arranged between the first absorption tower and the second absorption tower for pumping the absorption-state carbon dioxide absorbent at the bottom of the second absorption tower into the top of the first absorption tower; A lean liquid cooler arranged on the lean liquid pipeline connected to the spray head for cooling the carbon dioxide absorbent after the release of carbon dioxide flowing through the lean liquid pipeline; A filter arranged between the lean liquid cooler and the spray head for filtering the carbon dioxide absorbent after the release of carbon dioxide flowing through the lean liquid pipeline.

3. The low-concentration carbon dioxide recovery and purification device according to claim 2, characterized in that, The regeneration component includes: A rich-lean liquid heat exchanger connected to the first rich liquid pump through a rich liquid pipeline and connected to the lean liquid cooler through the lean liquid pipeline for heat exchange between the carbon dioxide absorbent after the release of carbon dioxide flowing through the lean liquid pipeline and the absorption-state carbon dioxide absorbent flowing through the rich liquid pipeline; A regeneration tower connected to the rich-lean liquid heat exchanger through a rich liquid pipeline for releasing carbon dioxide in the absorption-state carbon dioxide absorbent to obtain gaseous carbon dioxide; A lean liquid pump connected to the bottom of the regeneration tower for pumping the carbon dioxide absorbent after the release of carbon dioxide at the bottom of the regeneration tower into the lean liquid pipeline. A gas output pipeline, which is connected to the top of the desorption tower for outputting the gaseous carbon dioxide.

4. The low-concentration carbon dioxide recovery and purification device according to claim 3, characterized in that, The detection unit includes: A first carbon dioxide concentration sensor, which is arranged in the intake passage of the cooling water scrubbing tower in the water scrubbing and desulfurization unit for detecting the carbon dioxide concentration before cooling water scrubbing; A second carbon dioxide concentration sensor, which is arranged in the gas output pipeline for detecting the carbon dioxide concentration in the gas output pipeline; A third carbon dioxide concentration sensor, which is arranged in the first absorption tower for detecting the carbon dioxide concentration in the first absorption tower; A first gas flow sensor, which is arranged in the intake passage of the cooling water scrubbing tower in the water scrubbing and desulfurization unit for detecting the flow rate of the raw gas flowing through the intake passage; A second gas flow sensor, which is arranged in the gas output pipeline for detecting the flow rate of carbon dioxide in the gas output pipeline; An ultrasonic flowmeter, which is arranged at the gas inlet of the second absorption tower for detecting the gas rising speed of the raw gas at the gas inlet of the second absorption tower; An online pH sensor, which is arranged at the bottom of the second absorption tower for detecting the pH value of the carbon dioxide absorbent at the bottom of the second absorption tower to determine the carbon dioxide absorption amount of the carbon dioxide absorbent.

5. The low-concentration carbon dioxide recovery and purification device according to claim 4, wherein The control unit is connected to the first carbon dioxide concentration sensor, the second carbon dioxide concentration sensor, the first gas flow sensor and the second gas flow sensor, and is used to respectively obtain the carbon dioxide concentration before cooling water scrubbing, the carbon dioxide concentration in the gas output pipeline, the flow rate of the raw gas in the intake passage and the flow rate of carbon dioxide in the gas output pipeline. According to the carbon dioxide concentration before cooling water scrubbing and the flow rate of the raw gas in the intake passage, the initial detection amount of carbon dioxide in the raw gas is determined. According to the carbon dioxide concentration in the gas output pipeline and the flow rate of carbon dioxide in the gas output pipeline, the carbon dioxide output amount of the desorption component is determined. According to the difference between the initial detection amount of carbon dioxide in the raw gas and the carbon dioxide output amount of the desorption component, the recovery state of carbon dioxide is determined. Among them, If the ratio of the difference to the initial detection amount is greater than or equal to the preset loss ratio, it is determined that the carbon dioxide recovery is abnormal, and the carbon dioxide concentration, the gas rising speed, the carbon dioxide absorption amount, the flow rate of the raw gas and the flow rate of carbon dioxide are collected to further determine the abnormal state; If the ratio of the difference to the initial detection amount is less than the preset loss ratio, it is determined that the carbon dioxide recovery is normal.

6. The low-concentration carbon dioxide recovery and purification device according to claim 5, wherein, The initial detection amount is the integral value of the product of the function of the carbon dioxide concentration before cooling water scrubbing with respect to time and the function of the flow rate of the raw gas in the intake passage with respect to time within a preset sampling period.

7. The low-concentration carbon dioxide recovery and purification device according to claim 6, characterized in that, The carbon dioxide output amount is the integral value of the product of the function of the carbon dioxide concentration in the gas output pipeline with respect to time and the function of the flow rate of carbon dioxide in the gas output pipeline within a preset sampling period.

8. The low-concentration carbon dioxide recovery and purification device according to claim 7, wherein The control unit is connected to the nozzle, and is used to further determine that the nozzle is abnormal according to that the gas rising speed is less than the first preset gas rising speed and the carbon dioxide absorption amount is greater than the preset carbon dioxide absorption amount, and increase the pressure of the nozzle.

9. The low-concentration carbon dioxide recovery and refining device according to claim 8, wherein, The control unit is connected to the moving component, and is used to further determine that the vertical height of the nozzle is abnormal according to that the gas rising speed is greater than or equal to the first preset gas rising speed and less than the second preset gas rising speed and according to that the carbon dioxide absorption amount is less than or equal to the preset carbon dioxide absorption amount, and increase the vertical height of the nozzle through the moving component.

10. The low-concentration carbon dioxide recovery and purification device according to claim 9, wherein, The control unit is connected to the rich liquid cooler, and is used to further determine that the temperature of the rich liquid cooler is abnormal according to that the increase amount of the carbon dioxide concentration in the first absorption tower is greater than the preset carbon dioxide concentration increase amount, and reduce the temperature of the rich liquid cooler.

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